
export class sha1 {

  /*
 * Configurable variables. You may need to tweak these to be compatible with
 * the server-side, but the defaults work in most cases.
 */
  hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase        */
  b64pad  = ""; /* base-64 pad character. "=" for strict RFC compliance   */

  /*
 * These are the functions you'll usually want to call
 * They take string arguments and return either hex or base-64 encoded strings
 */
  hex_sha1(s) {
    return this.rstr2hex(this.rstr_sha1(this.str2rstr_utf8(s)));
  }

  b64_sha1(s) {
    return this.rstr2b64(this.rstr_sha1(this.str2rstr_utf8(s)));
  }

  any_sha1(s, e) {
    return this.rstr2any(this.rstr_sha1(this.str2rstr_utf8(s)), e);
  }

  hex_hmac_sha1(k, d) {
    return this.rstr2hex(this.rstr_hmac_sha1(this.str2rstr_utf8(k), this.str2rstr_utf8(d)));
  }

  b64_hmac_sha1(k, d) {
    return this.rstr2b64(this.rstr_hmac_sha1(this.str2rstr_utf8(k), this.str2rstr_utf8(d)));
  }

  any_hmac_sha1(k, d, e) {
    return this.rstr2any(this.rstr_hmac_sha1(this.str2rstr_utf8(k), this.str2rstr_utf8(d)), e);
  }

  /*
 * Perform a simple self-test to see if the VM is working
 */
  sha1_vm_test() {
    return this.hex_sha1("abc").toLowerCase() == "a9993e364706816aba3e25717850c26c9cd0d89d";
  }

  /*
 * Calculate the SHA1 of a raw string
 */
  rstr_sha1(s) {
    return this.binb2rstr(this.binb_sha1(this.rstr2binb(s), s.length * 8));
  }

  /*
 * Calculate the HMAC-SHA1 of a key and some data (raw strings)
 */
  rstr_hmac_sha1(key, data) {
    var bkey = this.rstr2binb(key);
    if (bkey.length > 16) bkey = this.binb_sha1(bkey, key.length * 8);

    var ipad = Array(16), opad = Array(16);
    for (var i = 0; i < 16; i++) {
      ipad[i] = bkey[i] ^ 0x36363636;
      opad[i] = bkey[i] ^ 0x5C5C5C5C;
    }

    var hash = this.binb_sha1(ipad.concat(this.rstr2binb(data)), 512 + data.length * 8);
    return this.binb2rstr(this.binb_sha1(opad.concat(hash), 512 + 160));
  }

  /*
 * Convert a raw string to a hex string
 */
  rstr2hex(input) {
    try {
      this.hexcase
    } catch (e) {
      this.hexcase = 0;
    }
    var hex_tab = this.hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
    var output = "";
    var x;
    for (var i = 0; i < input.length; i++) {
      x = input.charCodeAt(i);
      output += hex_tab.charAt((x >>> 4) & 0x0F)
      + hex_tab.charAt(x & 0x0F);
    }
    return output;
  }

  /*
 * Convert a raw string to a base-64 string
 */
  rstr2b64(input) {
    try {
      this.b64pad
    } catch (e) {
      this.b64pad = '';
    }
    var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    var output = "";
    var len = input.length;
    for (var i = 0; i < len; i += 3) {
      var triplet = (input.charCodeAt(i) << 16)
      | (i + 1 < len ? input.charCodeAt(i + 1) << 8 : 0)
      | (i + 2 < len ? input.charCodeAt(i + 2) : 0);
      for (var j = 0; j < 4; j++) {
        if (i * 8 + j * 6 > input.length * 8) output += this.b64pad;
        else output += tab.charAt((triplet >>> 6 * (3 - j)) & 0x3F);
      }
    }
    return output;
  }

  /*
 * Convert a raw string to an arbitrary string encoding
 */
  rstr2any(input, encoding) {
    var divisor = encoding.length;
    var remainders = Array();
    var i, q, x, quotient;

    /* Convert to an array of 16-bit big-endian values, forming the dividend */
    var dividend = Array(Math.ceil(input.length / 2));
    for (i = 0; i < dividend.length; i++) {
      dividend[i] = (input.charCodeAt(i * 2) << 8) | input.charCodeAt(i * 2 + 1);
    }

    /*
   * Repeatedly perform a long division. The binary array forms the dividend,
   * the length of the encoding is the divisor. Once computed, the quotient
   * forms the dividend for the next step. We stop when the dividend is zero.
   * All remainders are stored for later use.
   */
    while (dividend.length > 0) {
      quotient = Array();
      x = 0;
      for (i = 0; i < dividend.length; i++) {
        x = (x << 16) + dividend[i];
        q = Math.floor(x / divisor);
        x -= q * divisor;
        if (quotient.length > 0 || q > 0)
        quotient[quotient.length] = q;
      }
      remainders[remainders.length] = x;
      dividend = quotient;
    }

    /* Convert the remainders to the output string */
    var output = "";
    for (i = remainders.length - 1; i >= 0; i--)
    output += encoding.charAt(remainders[i]);

    /* Append leading zero equivalents */
    var full_length = Math.ceil(input.length * 8 /
    (Math.log(encoding.length) / Math.log(2)))
    for (i = output.length; i < full_length; i++)
    output = encoding[0] + output;

    return output;
  }

  /*
 * Encode a string as utf-8.
 * For efficiency, this assumes the input is valid utf-16.
 */
  str2rstr_utf8(input) {
    var output = "";
    var i = -1;
    var x, y;

    while (++i < input.length) {
      /* Decode utf-16 surrogate pairs */
      x = input.charCodeAt(i);
      y = i + 1 < input.length ? input.charCodeAt(i + 1) : 0;
      if (0xD800 <= x && x <= 0xDBFF && 0xDC00 <= y && y <= 0xDFFF) {
        x = 0x10000 + ((x & 0x03FF) << 10) + (y & 0x03FF);
        i++;
      }

      /* Encode output as utf-8 */
      if (x <= 0x7F)
      output += String.fromCharCode(x);
      else if (x <= 0x7FF)
      output += String.fromCharCode(0xC0 | ((x >>> 6) & 0x1F),
        0x80 | (x & 0x3F));
      else if (x <= 0xFFFF)
      output += String.fromCharCode(0xE0 | ((x >>> 12) & 0x0F),
        0x80 | ((x >>> 6) & 0x3F),
        0x80 | (x & 0x3F));
      else if (x <= 0x1FFFFF)
      output += String.fromCharCode(0xF0 | ((x >>> 18) & 0x07),
        0x80 | ((x >>> 12) & 0x3F),
        0x80 | ((x >>> 6) & 0x3F),
        0x80 | (x & 0x3F));
    }
    return output;
  }

  /*
 * Encode a string as utf-16
 */
  str2rstr_utf16le(input) {
    var output = "";
    for (var i = 0; i < input.length; i++)
    output += String.fromCharCode(input.charCodeAt(i) & 0xFF,
      (input.charCodeAt(i) >>> 8) & 0xFF);
    return output;
  }

  str2rstr_utf16be(input) {
    var output = "";
    for (var i = 0; i < input.length; i++)
    output += String.fromCharCode((input.charCodeAt(i) >>> 8) & 0xFF,
      input.charCodeAt(i) & 0xFF);
    return output;
  }

  /*
 * Convert a raw string to an array of big-endian words
 * Characters >255 have their high-byte silently ignored.
 */
  rstr2binb(input) {
    var output = Array(input.length >> 2);
    for (var i = 0; i < output.length; i++)
    output[i] = 0;
    for (var i = 0; i < input.length * 8; i += 8)
    output[i>>5] |= (input.charCodeAt(i / 8) & 0xFF) << (24 - i % 32);
    return output;
  }

  /*
 * Convert an array of big-endian words to a string
 */
  binb2rstr(input) {
    var output = "";
    for (var i = 0; i < input.length * 32; i += 8)
    output += String.fromCharCode((input[i>>5] >>> (24 - i % 32)) & 0xFF);
    return output;
  }

  /*
 * Calculate the SHA-1 of an array of big-endian words, and a bit length
 */
  binb_sha1(x, len) {
    /* append padding */
    x[len >> 5] |= 0x80 << (24 - len % 32);
    x[((len + 64 >> 9) << 4) + 15] = len;

    var w = Array(80);
    var a = 1732584193;
    var b = -271733879;
    var c = -1732584194;
    var d = 271733878;
    var e = -1009589776;

    for (var i = 0; i < x.length; i += 16) {
      var olda = a;
      var oldb = b;
      var oldc = c;
      var oldd = d;
      var olde = e;

      for (var j = 0; j < 80; j++) {
        if (j < 16) w[j] = x[i + j];
        else w[j] = this.bit_rol(w[j-3] ^ w[j-8] ^ w[j-14] ^ w[j-16], 1);
        var t = this.safe_add(this.safe_add(this.bit_rol(a, 5), this.sha1_ft(j, b, c, d)),
        this.safe_add(this.safe_add(e, w[j]), this.sha1_kt(j)));
        e = d;
        d = c;
        c = this.bit_rol(b, 30);
        b = a;
        a = t;
      }

      a = this.safe_add(a, olda);
      b = this.safe_add(b, oldb);
      c = this.safe_add(c, oldc);
      d = this.safe_add(d, oldd);
      e = this.safe_add(e, olde);
    }
    return Array(a, b, c, d, e);

  }

  /*
 * Perform the appropriate triplet combination for the current
 * iteration
 */
  sha1_ft(t, b, c, d) {
    if (t < 20) return (b & c) | ((~b) & d);
    if (t < 40) return b ^ c ^ d;
    if (t < 60) return (b & c) | (b & d) | (c & d);
    return b ^ c ^ d;
  }

  /*
 * Determine the appropriate additive constant for the current iteration
 */
  sha1_kt(t) {
    return (t < 20) ? 1518500249 : (t < 40) ? 1859775393 :
                                       (t < 60) ? -1894007588 : -899497514;
  }

  /*
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
 * to work around bugs in some JS interpreters.
 */
  safe_add(x, y) {
    var lsw = (x & 0xFFFF) + (y & 0xFFFF);
    var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
    return (msw << 16) | (lsw & 0xFFFF);
  }

  /*
 * Bitwise rotate a 32-bit number to the left.
 */
  bit_rol(num, cnt) {
    return (num << cnt) | (num >>> (32 - cnt));
  }
}